The conventional prior art massage chair drive mechanism 10, as shown in FIG. 5, is comprised of a main body 11, a kneading shaft 12, a spiral gear 14, a beating shaft 16, a worm gear 18, a main shaft 20 and a clutch 22.
The main body 11 is formed of two parts.
The kneading shaft 12 is rotatably mounted vertically and transverse of the main body 11. The kneading shaft 12 has a gear 13 which fits concentrically around the kneading shaft 12 and is fixedly connected to the kneading shaft 12. The gear 13 is rotatably mounted inside of and in the same plane as the main body 11. Gear 13 rotates in the horizontal plane of the main body 11. Both ends of the kneading shaft 12 extend outside the top and bottom parts of the main body 11.
The spiral gear 14 is rotatably mounted inside of and in a vertical transverse plane to the main body 11 and engages transversely with the gear 13 of the kneading shaft 12. The spiral gear 14 rotates in the vertical plane, which is transverse to the main body 11. The end of the spiral gear 14, which faces into the main body, has a face gear (not shown).
The beating shaft 16 is rotatably mounted vertically and transverse of the main body 11. The beating shaft 16 has a gear 17 which fits concentrically around and is fixedly connected to the beating shaft 16. The gear 17 is rotatably mounted inside of and in the same plane as the main body 11. Gear 17 rotates in the horizontal plane of the main body 11. Both ends of the beating shaft extend outside the top and bottom parts of the main body 11.
The worm gear 18 is rotatably mounted inside of and in a vertical transverse plane to the main body 11 and engages transversely with the gear 17 of the beating shaft 16. The worm gear 18 rotates in the vertical plane, which is transverse to the main body 11. The end of the worm gear 18, which faces into the main body has a face gear 19. The worm gear 18 is linearly aligned with the spiral gear 14 and on the same axis as spiral gear 14 within the main body 11.
The main shaft 20 is driven by the motor and rotatably mounted within the main body 11 so that the main shaft 20 extends through the linearly aligned spiral gear 14 and the worm gear 18. The main shaft 20 is rotatably mounted within spiral gear 14 and the worm gear 18 so that main shaft 20 can freely rotate without engaging either the spiral gear 14 or the worm gear 18. The plane of rotation for the main shaft 20 is the same rotation plane as both the spiral gear 14 and the worm gear 18. Both ends of the main shaft 20 extend outside the sides of the main body 11. The middle section 21 of the main shaft 20 fits between the spiral gear 14 and the worm gear 18 and has a larger diameter hexagonal-shaped tube body. The middle section 21 does not engage either the spiral gear 14 or the worm gear 18.
The clutch 22 is a tubular member with a hexagonal-shaped through hole 23 which fixedly engages the middle section 21 of the main shaft 20 so that rotation of the main shaft 20 and middle section 21 will cause the clutch 22 to similarly rotate. The clutch is located within the main body 11 between the spiral gear 14 and the worm gear 18. The opposite ends of the clutch 22 have end gears 24 which corresponding to the face gear of the spiral gear 14 and face gear 19 of the worm gear 18.
The end gears 24 of the clutch 22 have teeth to engage the face gears. When the teeth of the end gear 24 engage the teeth of the face gear associated with the spiral gear 14, the corresponding spiral gear 14 rotates and causes the kneading shaft 12 to knead. When the opposite end gear 24 engages the teeth of the face gear 19, the corresponding worm gear 18 rotates and causes the beating shaft 16 to beat. The shape of the teeth of the end gears 24 consist of a quarter-circular shape with a planar edge and a rounded arc edge. The shape of the teeth of the face gears consist of the same quarter-circular shape with a planar edge and a rounded arc edge. The end gear 24 engages the face gear with the planar edges of the teeth are aligned to allow the rotational thrust of the end gear 24 to be applied to the face gear and the corresponding spiral or worm gear. The teeth of the end gear 24 are aligned in opposite directions so that the teeth can only engage a single face gear at one time, depending on whether the main shaft 20 rotates forward or reverse. The clutch 22 works to engage either the spiral gear 14 or the worm gear 18 to achieve the functions of kneading or beating.
However, the prior art drive mechanism is defective. First, the kneading and beating functions cannot be operated at the same time. The clutch 22 makes only two selections for separate massage operations. Also, the changing between kneading and beating functions depends upon whether the main shaft 20 rotates forward or reverse, which diminishes the life of the motor. Furthermore, the burden of switching between forward and reverse decreases the durability of the clutch 22. Thus, the life of the massage drive mechanism 10 is shortened.